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400 ISL Water Leak

March 18, 2014, 10:24:13 pm

I have a 2003 (build # 6180) with a 400 Cummins ISL.

After a recent cold spell inn Houston I noticed a water leak that appears to be coming from a round piece that the serpentine belt wraps around. Doesn't look like the typical pulley because it is just flat. (pictures are attached).

My rough guess is this has something to do with the water pump. The shaft on this piece goes through a thick metal plate (triangular shaped). It appears that the leak may be coming from behind this piece - possible from a seal around a the shaft. Can't really tell without doing some disassembly.

Is this where the water pump is located? Has anyone had a similar leak and is it a weekend mechanic job to pull the piece and replace the seal if there is one that may be leaking?

jack

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Re: 400 ISL Water Leak

Reply #1 – March 19, 2014, 12:31:38 am

I have a Cummins 8.3 (ISC).  That is how my coach looked when the water pump seal went out.

 NAPA had a rebuilt water pump for $ 137.00 in 2009 (plus $36 core charge).  I bought two 5 gallon buckets and drained 8 gallons of coolant from the radiator petcock, then changed out the water pump myself.  Not too hard of a job.  My coolant was in good shape so I strained it back into the engine after repair. 

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Re: 400 ISL Water Leak

Reply #2 – March 19, 2014, 06:49:35 am

I have an ISM but changed my water pump too it started weeping so before it died I pulled it.  Usually. Shows up in cold weather first with me as well I did mine two years ago. So it is about right in time. 

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Re: 400 ISL Water Leak

Reply #3 – March 19, 2014, 08:50:23 am

Thanks for the expert advise.

It is so great having a place to go for advise and experiences.

Sure helps me out and provides the confidence needed.


jack

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Re: 400 ISL Water Leak

Reply #4 – March 19, 2014, 08:57:09 am

Jack, That is the water pump.  Be aware that the lower streetside bolt also secures the strap that holds the alternator in position.  This bolt tends to wallow out the flange on the pump and break off.  Before changing the pump move the tensioner out of the way and see if the leak is at this bolt, if so you may be able to replace the bolt and the leak will stop.  You may also have to clean up the threads in the block.
Good luck
Gary B

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Re: 400 ISL Water Leak

Reply #5 – March 19, 2014, 10:11:19 am

Thanks Gary.

I will be sure to ck that before I get too far in.

I am thinking I should probably replace tensioners while down. What do you think?


jack

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Re: 400 ISL Water Leak

Reply #6 – March 19, 2014, 10:42:51 am

Jack, Yep, that looks like the original tensioner, do a search and you will find a lot of info on them.
Gary B

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Re: 400 ISL Water Leak

Reply #7 – March 20, 2014, 01:05:03 pm

You are lucky you have warning before being stranded on the road.  Mine failed on I-95 in South Carolina in January.  Made a wonderful mess.  The pump was so loose the bearings where dropping out.    The new part impeller seems to be much more efficient -- to the naked eye --- lets hope the bearings are stronger as well.

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